.preview-waves {
  position: relative;
  width: 100%;
  height: 15vh;
  margin-bottom: -7px;
  min-height: 100px;
  max-height: 150px;
}
 .preview-parallax > use {
  animation: move-forever 25s cubic-bezier(0.55, 0.5, 0.45, 0.5) infinite;
}
 .preview-parallax > use:nth-child(1) {
  animation-delay: -2s;
  animation-duration: 7s;
}
 .preview-parallax > use:nth-child(2) {
  animation-delay: -3s;
  animation-duration: 10s;
}
.preview-parallax > use:nth-child(3) {
  animation-delay: -4s;
  animation-duration: 13s;
}
 .preview-parallax > use:nth-child(4) {
  animation-delay: -5s;
  animation-duration: 20s;
}

// ============================================================================
// css 动画
@-moz-keyframes move-forever {
  0% {
    transform: translate3d(-90px, 0, 0);
  }
  100% {
    transform: translate3d(85px, 0, 0);
  }
}
@-webkit-keyframes move-forever {
  0% {
    transform: translate3d(-90px, 0, 0);
  }
  100% {
    transform: translate3d(85px, 0, 0);
  }
}
@-o-keyframes move-forever {
  0% {
    transform: translate3d(-90px, 0, 0);
  }
  100% {
    transform: translate3d(85px, 0, 0);
  }
}
@keyframes move-forever {
  0% {
    transform: translate3d(-90px, 0, 0);
  }
  100% {
    transform: translate3d(85px, 0, 0);
  }
}
@-moz-keyframes blink {
  0% {
    opacity: 1;
  }
  50% {
    opacity: 0;
  }
  100% {
    opacity: 1;
  }
}
@-webkit-keyframes blink {
  0% {
    opacity: 1;
  }
  50% {
    opacity: 0;
  }
  100% {
    opacity: 1;
  }
}
@-o-keyframes blink {
  0% {
    opacity: 1;
  }
  50% {
    opacity: 0;
  }
  100% {
    opacity: 1;
  }
}
@keyframes blink {
  0% {
    opacity: 1;
  }
  50% {
    opacity: 0;
  }
  100% {
    opacity: 1;
  }
}
@media (min-width: 768px) {
  .post {
    padding-top: 45px;
  }
}
// css 动画结束
// =============================================================================